Process for making elastic bulky composite yarn



Dec. 19, 1961 A. BREEN PROCESS FOR MAKING ELASTIC BULKY COMPOSITE YARN Filed July 5, 1960 FIG.I

INVENTOR A LVlN LEONARD BREEN BY wa y-1nd, f.

ATTORNEY hired htates This invention relates to novel textile products and particularly to yarns and fabrics having high bulk, high stretch and high power, and processes for producing same.

High bulk yarns enjoy wide acceptance in apparel fabrics. Such fabrics have either no stretch properties whatsoever or at most exhibit small or moderate stretchability.

According to this invention there is provided an elastic bulky composite yarn preferably having coils, loops, and whorls and comprising a continuous filament elastomeric fiber yarn as the core and a continuous filament hard fiber yarn as the sheath. The invention also includes a process for preparing these composite yarns which comprises feeding simultaneously a continuous filament elastomeric fiber strand and a continuous filament hard fiber strand together through a jet of high velocity (at least /2 sonic) compressible fluid, and Winding up the resulting strand under a tension such that the elastomeric strand is elongated between 100% and 600% based on it length at zero tension. in passing through the jet of fluid the filaments in the strands are whipped about violently and interentangled and interentwined to form a composite strand. The hard fiber strand is fed to the fluid jet at an overfeed of 5% to l000%, and the temperature of the zone of iluid turbulence is between room temperature and the temperature at which any of the filaments become tacky, preferably below 375 C.

The invention will be better understood by referring to the drawings.

FIGURE 1 illustrates schematically one procedure of this invention.

FlGURES 2a, 2b and 3a, 3b show schematically typical yarn products of this invention.

In FIGURE 1, two hard fiber ends 1 and 1' are fed through tension gate 2 through feed rolls 3 to fluid jet 4 while elastomeric fiber strand 5 is simultaneously fed to the same jet. Air is fed to the fluid jet by means not shown and forms a turbulent zone which whips the filamerits about violently within the jet, producing a composite strand 6 thereby which is wound up on roll '7 at a tension suflicient to elongate the elastomeric fiber strand between 100% and 600%. The drawing shows schematically a typical strand thus produced in extended form (FIGURE 2a) and relaxed (FIGURE 25).

FiGURE 1 also illustrates how additional trands may be simultaneously passed through the fiuid jet. For example, bard fibers 8 and 8' may be simultaneously passed through tension gate 9, feed rolls 10, to fluid jet 4 along with the hard fibers 1 and l and elastomeric fiber 5. If the additional hard fibers 8 and 3 are fed to the jet at the same speed as the windup speed of roll 7 while hard fibers El and l are overfed to the jet and elastomeric fiber undergoes an elongation of between 100% and 600% due to the windup tension, composite strands shown schematically in FIGURE 3a (extended) and FIGURE 31) (relaxed) are produced.

The elastomeric strand for use in this invention may be any continuous multifilament or monofilament strand, preferably the former, having a denier between about 20 and about 560, preferably 20140, since the finer the denier, the better the control of the texturing process and the better the uniformity of the product. A condensation elastomer will usually form fibers having a tensile form recovery above about and a stress decay below about 35 Elastomeric filaments may be prepared from either condensation elastomers or addition elastomers. Sog- 1nented clastorners, which comprise the broadest class of polymers having fiber-forming and elastomeric properties, are prepared by starting with a low molecular weight polymer (i.e., one having a molecular weight in the range from about 700 to about 3500), preferably a difunctional polymer with terminal groups containing active hydrogen, and reacting it with a small co-reactive molecule under conditions such that a new difunctional intermediate is obtained with terminal groups capable of reacting with active hydrogen. The intermediates are then coupled or chain-extended by reacting with compounds containing active hydrogen. Exemplary low molecular weight starting polymers are polyesters and polyesteramides and an exemplary co-reactive small molecule is a diisocyanate. A large variety of co-reactive hydrogen compounds may be used in preparing the segmented condensation elastorners. Among the most practical chain-extending agents are water, diamines, and dibasic acids.

U.S. 2,692,873 to Langerak et al. describes similar products in which the starting polyesters have been replaced by polyethers of a corresponding molecular weight range. A number of macromolecular compounds, such as polyhydrocarbons, polyamides, polyur thanes, etc., with suitable molecular weights, melting point characteristics, and terminal groups, can serve as the starting point for preparing segmented elastorners of this type.

Other types of condensation elastomers are also suitable. U.S. 2,670,267 to Bredeson describes Nalkylsubstituted copolyamides which are highly elastic and have a suitable low modulus. A copolyarnide of this type, obtained by reacting adipic acid with a mixture of hexamethylenediarnine, N-isobutylhexamethylenediamine, and hLNdsobutylhexamethylenediamine, produces an elastorner which is particularly satisfactory for the purposes of this invention. US. 2,623,033 to Snyder describes linear elastic copolyesters prepared by reacting glycols with a mixture of aromatic and acyclic dicarboxylic acids. Copolymers prepared from ethylene glycol, terephthalic acid, and sebacic acid have been found to be particularly useful. Another class of useful condensation elastomers is described in US. 2,430,860 to Cairns. Elastomeric polyamides of this patent may be produced by reacting polycarbonamides with formaldehyde.

Suitable elastorners may also be found among fiberforming addition polymers such as, for example, copolymers of butadiene/styrene, butadiene/acrylonitrile and butadiene/Z-vinyl pyridine, polychlorobutadiene, copolymers of isobutylene with small proportions of butadiene, chlorosulfonated polyethylene, copolyrners of monochlorotrifiuoroethylene with vinylidene fluoride, and the like.

Hard (non-elastomeric) fiber strands useful in this invention may be any ordinary commercial continuous multitilarnent or monofilament hard fiber strand suitable for processing on conventional textile equipment for preparing ordinary apparel fabrics or the like, and may be prepared from an synthetic fiber-forming materials, such as polyesters (e.g., polyethylene terephthalate), polyarnides (e.g., polyhexamethylene adipamide, polyhexamethylene sebacarnide, polycaproamide, and copolymers of various amides), acrylic polymers and copolymers (e.g., polyacrylonitrile, copolymers of acrylonitrile with vinyl chloride, vinylidene cyanide, vinyl pyridine, methyl acrylate), vinyl polymers (e.g., vinyl chloride/vinyl acetate copolyrners), polymers and copolymers of tetrafluoroethylene, monochlorotrifluoroethylene, and hexafluoropr'opylene, polyolefins such as polyethylene, cellulose derivatives (cg, cellulose acetate, regenerated cellulose, ethyl cellulose, cellulose triacetate), glass, or from any continu- 3 ous filament natural fiber, such as sills, or there may be used a blend of two or more continuous filament hard fibers.

The term elastic as used herein has the r e-hing conveutionally given to that term in the art and is ap d herein to describe a synthetic filQutGfEEIlC continuous filament capable of at least 100% elongation before breaking. Elastic fibers utilized in this invention pr crasly will undergo between about 500% and about 000% eloi gstion before breaking and have a modulus (force quired to stretch to a specified elongation) of about or less. This is in contrast to hard fibers which are erally characterized by a modulus between about lo about 35 and which usually will stretch no more than about 20-40% before breaking. The elastic fibers of this invention are not only characterized by very high strat ability, but also by very quick recovery (almost instan neous) to the original uncrimped condition. Stretchability of the elastic fiber does not depend upon crimping or twisting. The hard fiber denier may be any avz. ole denier, such as 20-3000. A preferred denier range for the hard fiber is 70-300.

In addition to air as the preferred compres ible fluid for use in the co-teaturing of this invention, there may be used other compressible fluids such as steam, nitrogen, carbon dioxide, and the like. However, the fluid used and the temperature of the fluid in the region of turbul nt action should be inert to all the fibers processed and the temperature should be below the stick temperature of all the fibers used in the process. The max runr tempt-n ature will be chosen depending upon the. stick temperature of the elastomeric fiber, and rhis maximum will u-crmall be below the stick temperature in order to avo d to the fiber during processing. Various t invention, such as the fluid jets described in .t

Patent 2,783/ and in copending applications of nail,

S.N. 604,564, filed August 16, 1956, and new US, Patent den and Murenbeeld, SN. 781,549, filed December l;

yarn having loops, coils, and whorls.

The windup tension applied to the composite yarn product of this invention is critical and is determined by the elastomeric filament utilized. Windup tension should be controlled to provide from 100% to 600% elon ttion of the elastomeric strand, preferably 100-250% elongation, based upon zero tension length of the strand. The hard fiber is fed to the turbulent region under conditions of -l000% overfeed, and preferably 100-30095 over the speed of the windup end. When using air the tr out fluid, air pressure in the range of 20-100 p.s.i.g. will normally be used, and preferably 60-75 psig. Low ranges of air pressure such as 20-60 p.s.i.g. produce fluffy, fuzzy type yarns, intermediate air pressures yield smooth type yarns and the higher air pressures such as 75-l00 p.s.i.g. yield fuzzy type yarns.

An important advantage of this invention is that it provides novel yarns and fabrics which have a combination of high bulk, high stretch and high power characteristics. The critical conditions of the process for co-texturing the hard and elastomeric continuous filaments may be adjusted within the stated limits to produce yarns which lead to a variety of different types of fabric properties. The resulting fabrics all have good aesth tics and good cover, and may be characterized as suede-like properties, boucle fabrics, plisse fabrics, or smooth fabrics.

The novel yarns of this invention may be woven or knitted into various types of fabrics which may be used for a variety of purposes such as upholstery, girdles, knitwear, swii. -wear, elastic waist-bands, sock tops, medical bandages, flannels, velvets, satin fabrics and a wide variety of other apparel and industrial fabrics.

Elastic core-spun yarns containing a continuous filamerit core of elastic yarn and a sheath of drafted staple fibers spun around the core may be prepared by introducing the untwisted elastic yarn to tr e back drafting rolls of a spinning frame between two or more ends of roving from conventional staple fibers. This technique Works particularl' well when a continuous-filament spandex yarn, i.e., a segmented polyurethane, is used for the core yarn. This process is more economical than previous methods, since neither pre-twisting nor metering of the core is required. Since the mechanical draft applied to the staple fibers in the spinning frame may exceed the breaking elongation of the elastic yarn, some slippage of the elastic yarn takes place in the drafting zone. Nevertheless, with. spandex yarns, any such slippage appears to be quite uniform, and a very uniform core-spun yarn results.

The following example illustrates a specific embodiment of this invention.

EXAMPLE Four different filling yarns an woven fabrics are prepared for later measurement and comparison of properties, as follows:

Sample A Thee ends of multifilament yarn are fed simultaneously to a texturing er of the type shown in FIGURE 1 of copending application U.S. Serial No. 604,564 of Hall, filed August 16, 1956, and now U.S. Patent No. 2,958,112, using the processing arrangement illustrated in FIGURE 1 of the instant application. Air at gage pressure of 60 pounds per square inch is supplied to the jet at room temperature to act as the turbulent fluid. The hard fiber feed consists of two ends of polyhexamethylene adipamide continuous multifilament yarn each having 34 filaments, 70 total denier, and /2 turn per inch Z twist. These two ends of nylon yarn are overfed to the jet at a speed 300% greater than the co-textured yarn product is wound up, and one end of elastomeric yarn is fed to the same jet simultaneously. The elastomeric fiber yarn consists of one end of a continuous multifilament yarn having 16 filaments, 140 total denier, zero twist. This elastomeric fiber is a copolymer prepared by condensing poly(tetramethylene oxide) glycol (40 parts) having a molecular weight of 1,000 with 20 parts of methylene bis(4-phenylisocyanate). The polyether diurethane having isocyanate terminal groups is reacted with 2 grams of hydrazine monohydrate in N,N-dimethylformamide to produce a copolymer with an inherent viscosity of 2.2 in m-cresol solution. The elastomertic filaments are dry spun from this copolymer. The one end of elastomeric yarn is underfed to the jet, so that it is elongated 250% before windup. The resulting co-textured yarn of this invention is used as the filling in weaving a fabric having a warp of regular multifilament nylon yarn (70-34-18 2).

Sample B This sample fabric is woven using as the warp regular multifiiament nylon yarn (70-34-7 Z) and as the filling a textured nylon multifilament yarn (96T/ -68-13 2). The latter textured filling yarn is made by the process described in Us. Patent 2,783,609 to Breen, using room temperature air as the turbulent fluid and a yarn overfeed to the texturing jet of 16%.

Sample C This sample fabric is woven from two commercially available bulked yarns: one a polyhexamethylene adipamide yarn (70-34-0) in the warp, and the other polyethylene terephthalate yarn (70-34-0) in the fillin.

Sample D The filling yarn for this sample is made by wrapping in opposite directions two ends of 75 denier rayon yarn as a sheath around a core of 300 denier synthetic elastomeric yarn, having the same chemical composition as that of the elastomeric yarn in Sample A, using the same method as that used commercially for making wrapped (i.e., covered) rubber yarns. The warp yarn used in this sample fabric is regular multifilament nylon yarn (70-34-18 2).

The four sample fabrics are woven using the construction and type of weave shown in Table I. The filling yarn elongations and fabric properties are also listed in the table for each sample. The specific volume of the fabrics in Table I is a measure of the covering power of a fabric and is calculated as follows:

fabric thickness) opecific volume (0.743) fabric Weight The data reported in Table I show the superior properties of Sample A over those of the other samples with respect to higher stretch in the filling yarn as well as in the filling direction of the fabric, higher power, and better cover. The superior covering power of Sample A fabric over the other three fabrics is apparently due to greater bulk and body in this fabric. The Sample A fabric is particularly useful as a girdle fabric because of its combination of high bulk, high power, and high stretch properties, and the fact that finer denier yarns can be used to produce these properties than has been possible with girdle fabrics made of covered rubber yarns of the prior art. The power of a yarn refers to the recovery force at any elongation (within its elastic limits) tending to return the yarn to its original length.

I claim:

1. A process for producing a composite strand which comprises passing a hard fiber synthetic organic continuous filament strand and an elastomeric fiber synthetic organic continuous strand simultaneously through a turbulent zone formed by a jet of compressible fluid moving at at least /a sonic velocity, followed by winding up the resulting composite strand at a tension suflicient to elongate the elastomeric component between about and about 600% based upon its length under zero tension, said hard fiber strand being fed to the turbulent zone at an overfeed between about 5% and about 1000%, the temperature of the fluid in the turbulent zone being between about room temperature and the lowest temperature at which any of the fibers becomes tacky.

2. The process of claim 1 in which the fluid is air.

3. The process of claim 2 in which the elastomeric fiber strand is elongated between about 100% and about 250% and the hard fiber strand is overfed between about 100% and about 300%.

4. The process of claim 2 in which a second hard fiber strand is fed simultaneously through the turbulent zone at a rate equal to the windup rate.

References Cited in the file of this patent UNITED STATES PATENTS 2,324,989 Alderfer July 20, 1943 2,825,118 Sousslofi et al. Mar. 4, 1958 2,852,906 Breen Sept. 23, 1958 2,864,230 Moore Dec. 16, 1958 2,869,967 Breen Ian. 20, 1959 FOREIGN PATENTS 557,020 Belgium Oct. 26, 1957 828,641 Great Britain Feb. 24, 1960 

